The invention relates to a method for disposing of hazardous or high-energy materials, in which the latter are caused to undergo a reaction in a pressure-proof housing under controlled conditions, the end products of which reaction are non-hazardous,
as well as
an apparatus for disposing of hazardous or high-energy materials with a pressure-proof housing in which the materials may be caused to undergo a reaction under controlled conditions, the end products of which reaction are non-hazardous.
The xe2x80x9cdangerous or high-energyxe2x80x9d materials whose disposal is the aim of the present invention include in particular explosives or munitions, during the controlled explosion of which large amounts of mechanical and thermal energy are liberated. The invention is also suitable additionally, however, for the disposal of other dangerous substances which have to be converted to the desired non-hazardous end products with particular chemicals, in both exothermic and endothermic reactions.
It is known for the disposal of explosives or explosive materials to introduce the latter into a pressure-proof housing and to detonate them there in a controlled manner. An example of this is contained in WO 97/43594 A1. Disadvantageous with said known apparatuses or methods is that the disposal may take place only batch-wise and the course of the reaction is difficult to control.
The object of the present invention is to develop a method of the kind mentioned in the preamble is such a way that continuous operation is possible and the course of the reaction is easy to control.
This object is achieved according to the invention by the materials to be disposed of being mixed with a bulk material with which they together form a moving bed, wherein the reaction is initiated at a certain distance from the surface in the interior of the moving bed.
According to the invention the materials to be disposed of are therefore introduced jointly with the bulk material into the pressure-proof housing, in which a moving bed forms in the dynamic equilibrium. The latter admittedly retains its externally discernible shape substantially continuously; closer examination shows, however, that the materials of which the moving bed is formed are continuously in motion. In this way the materials to be disposed of may first of all be moved into a particular low part of the moving bed, where they are then caused to undergo a reaction. The surrounding moving bed at the same time absorbs energy which is released, in both mechanical and thermal form. The moving bed offersxe2x80x94where this is desiredxe2x80x94large surfaces on which a reaction may take place. Finally, the moving bed also represents a heat store which may ensure savings on energy at all points where the materials to be disposed of have to be brought to a reaction temperature. Bulk material and materials to be disposed of may be supplied to the moving bed in the mixed state or be xe2x80x9cscatteredxe2x80x9d onto the moving bed separately, so that the mixture forms at the earliest inside the moving bed.
If balls are used as bulk material, the required inner mobility of the moving bed is ensured particularly effectively. Deviations from the ball shape are possible, however, provided only that the degree of intrinsic friction of the bulk material is not such that the inner mobility of the moving bed is endangered.
The balls consist preferably of steel or ceramic. Both materials have the required strength to absorb mechanical or thermal energy and are in general resistant to the materials to be disposed of.
In very many cases the disposal reaction is initiated only at a particular temperature. In the most favourable case there may be set in the moving bed, without recourse to external energy and exclusively with the aid of the reaction heat, a temperature profile with which the reaction temperature is attained at a certain distance from the surface in the interior of the moving bed.
If however the materials to be disposed of are not sufficiently energy-rich to attain the reaction temperature, external heat must be supplied. This may take place in the simplest case by the supply of fuels or other ignition aids. Alternatively said heat input required for the attainment of the reaction temperature may also take place by means of an arc or inductively. In the latter case the moving bed must contain electrically conductive materials, e.g. steel balls, as bulk material.
Particularly advantageous is that development of the method according to the invention in which the bulk material is separated from the material mixture leaving the moving bed and is supplied again at least in part to the inlet of the moving bed. The consumption of the bulk material may be kept low in this way.
Auxiliaries essential for the carrying out of the method or promoting this may be supplied to the moving bed. Here are meant in particular fuels, which increase the temperature of the moving bed, air, which serves in particular for the supply of oxygen, temperature control gas, with which in particular a preliminary temperature control may take place in the area of the free surface of the moving bed, chemicals, with which the materials to be disposed of are to be reacted, and also chemisorption agents, which bind particular reaction products to themselves.
It is a further object of the present invention to develop an apparatus of the kind mentioned in the preamble in such a way that it may be operated continuously and the disposal reaction may be easily controlled.
This object is achieved according to the invention
by there being formed in the housing a moving bed moving in a top-to-bottom direction in the dynamic equilibrium between the supply of a bulk material and the materials to be disposed of on the one hand and the discharge of a mixture of bulk material and residual materials arising from the reaction on the other,
wherein a device is provided which ensures that the reaction is initiated only at a certain distance from the surface in the interior of the moving bed.
The advantages which are achievable with such an apparatus compared with those according to the prior art conform analogously to the advantages of the method according to the invention which were explained above. The same applies to the advantages of the embodiments of the apparatus according to the present invention.
Particularly worthy of mention at this point is the embodiment of the apparatus according to the invention as claimed in claim 18, in which the wall of the housing incorporates the following layers from the outside to the inside:
a) a pressure jacket;
b) a sound-absorbent layer;
c) an elastic layer;
d) a deformable shell of wear-resistant material supported by the elastic layer.
Said wall composition has proved to be particularly effective in coping with the complex tasks which the wall has to cope with in particular as regards the absorption of thermal and mechanical energy and also the sound dampening of noises.
The sound dampening layer may further consist of sand or wood, the elastic layer of an elastomer or a compressed fluid.
It is beneficial if temperature control ducts are passed through the elastic layer. As the result of a suitable medium flowing through said temperature control ducts, not only may reaction heat be dissipated, but in general a particular temperature profile be set in the moving bed in flow direction by cooling or heating. With hot working the inner shell may be additionally cooled, so that the higher toughness and strength of the material at lower temperatures may be exploited.
The wear-resistant (inner) shell of the wall is preferably provided with devices which permit an elastic change in diameter of the shell. The wear-resistant shell may then xe2x80x9cbreathexe2x80x9d for the absorption of pressure surges and in this way effectively release the mechanical energy to the elastic layer by which it is supported.